Solar panel inspection using unmanned aerial vehicles

Abstract

Methods, systems, and program products of inspecting solar panels using unmanned aerial vehicles (UAVs) are disclosed. A UAV can obtain a position of the Sun in a reference frame, a location of a solar panel in the reference frame, and an orientation of the solar panel in the reference frame. The UAV can determine a viewing position of the UAV in the reference frame based on at least one of the position of the Sun, the location of the solar panel, and the orientation of the solar panel. The UAV can maneuver to the viewing position and point a thermal sensor onboard the UAV at the solar panel. The UAV can capture, by the thermal sensor, a thermal image of at least a portion of the solar panel. A server onboard the UAV or connected to the UAV can detect panel failures based on the thermal image.

What is claimed is: 
     
       1. A system comprising:
 one or more processors; and 
 a non-transitory computer-readable medium including instructions that, when executed by the one or more processors, cause the system to:
 determine a flight path for an unmanned aerial vehicle (UAV) for inspection of one or more solar panels; 
 navigate the UAV according to the flight path; 
 obtain, at multiple geo-spatial locations, respective thermal images of the one or more solar panels; 
 determine, based on the obtained thermal images, that one or more solar cells of the one or more solar panels failed; and 
 responsively generate a report indicating that the one or more solar cells of the one or more solar panels failed. 
 
 
     
     
       2. The system of  claim 1 , wherein the instructions, when executed by the one or more processors, further cause the system to:
 obtain a position of the Sun in a reference frame, a location of a solar panel in the reference frame, and an orientation of the solar panel in the reference frame; 
 determine a viewing position of the UAV in the reference frame based on at least one of the position of the Sun, the location of the solar panel, and the orientation of the solar panel; and 
 maneuver the UAV to the viewing position. 
 
     
     
       3. The system of  claim 2 , wherein to obtain the position of the Sun, the system is configured to:
 obtain a time of capturing the thermal images; and 
 determine the position of the Sun based on the time of capturing the thermal images. 
 
     
     
       4. The system of  claim 2 , wherein to obtain the position of the Sun, the system is configured to:
 obtain an image of the sky by the UAV; 
 associate the image of the sky with the reference frame; and 
 determine the position of the Sun in the reference frame based on the image of the sky. 
 
     
     
       5. The system of  claim 2 , wherein to determine the viewing position, the system is configured to:
 determine a UAV position that is within a threshold distance from the location of the solar panel, and a viewing angle of a thermal sensor relative to the solar panel that reduces a reflection of the Sun from the solar panel; and 
 designate the UAV position as the viewing position. 
 
     
     
       6. The system of  claim 1 , wherein to determine that the one or more solar cells of the one or more solar panels failed, the system is configured to:
 compare a thermal image of a solar panel with one or more thermal images of one or more other thermal panels; and 
 determine that the solar panel failed upon determining that a difference between thermal energies represented in the thermal image and thermal energies represented in the one or more other thermal image exceeds a panel fail threshold. 
 
     
     
       7. The system of  claim 1 , wherein to determine that the one or more solar cells of the one or more solar panels failed, the system is configured to:
 determine, based on a thermal image, that thermal energy of a solar cell of the solar panel exceeds thermal energies of one or more other solar cells of the solar panel by at least a threshold difference amount; and 
 in response, determine that at the solar cell of the solar panel failed. 
 
     
     
       8. The system of  claim 1 , wherein to determine that the one or more solar cells of the one or more solar panels failed, the system is configured to:
 determine, based on a thermal image, that a string of solar cells of the solar panel are overheating; and 
 in response, determine that the string of solar cells failed. 
 
     
     
       9. The system of  claim 1 , wherein to determine that the one or more solar cells of the one or more solar panels failed, the system is configured to:
 determine, based on the thermal image, that at least a threshold number of overheating cells are randomly distributed in a solar panel; and 
 in response, determine that the solar panel failed. 
 
     
     
       10. The system of  claim 1 , wherein to determine that the one or more solar cells of the one or more solar panels failed, the system is configured to:
 determine, based on a thermal image, that a part of a solar cell of a solar panel is overheating; and 
 determine that the overheating solar cell failed due to a rupture. 
 
     
     
       11. The system of  claim 1 , wherein to determine that the one or more solar cells of the one or more solar panels failed, the system is configured to:
 determine, based on a thermal image, that a portion of a solar panel including multiple solar cells is overheating; and 
 determine that the solar panel failed due to one or more cracks at the portion of the solar panel. 
 
     
     
       12. A method implemented by a system comprising one or more processors, the method comprising:
 determining a flight path for an unmanned aerial vehicle (UAV) for inspection of one or more solar panels; 
 navigating the UAV according to the flight path; 
 obtaining, at multiple geo-spatial locations, respective thermal images of the one or more solar panels; 
 determining, based on the obtained thermal images, that one or more solar cells of the one or more solar panels failed; and 
 responsively generating a report indicating the failure. 
 
     
     
       13. The method of  claim 12 , comprising:
 obtaining a position of the Sun in a reference frame, a location of a solar panel in the reference frame, and an orientation of the solar panel in the reference frame; 
 determining a viewing position of the UAV in the reference frame based on at least one of the position of the Sun, the location of the solar panel, and the orientation of the solar panel; and 
 maneuvering the UAV to the viewing position. 
 
     
     
       14. The method of  claim 13 , wherein obtaining the position of the Sun comprises:
 obtaining a time of capturing the thermal images; and 
 determining the position of the Sun based on the time of capturing the thermal images. 
 
     
     
       15. The method of  claim 13 , wherein obtaining the position of the Sun comprises:
 obtaining an image of the sky by the UAV; 
 associating the image of the sky with the reference frame; and 
 determining the position of the Sun in the reference frame based on the image of the sky. 
 
     
     
       16. The method of  claim 13 , wherein determining the viewing position comprises:
 determining a UAV position that is within a threshold distance from the location of the solar panel, and determining a viewing angle of a thermal sensor relative to the solar panel that avoids or reduces a reflection of the Sun from the solar panel; and 
 designating the UAV position as the viewing position. 
 
     
     
       17. The method of  claim 12 , wherein determining that one or more solar cells of the one or more solar panels failed comprises:
 comparing the thermal image with one or more thermal images of one or more other thermal panels; and 
 determining that the solar panel failed upon determining that a difference between thermal energies represented in the thermal image and thermal energies represented in the one or more other thermal image exceeds a panel fail threshold. 
 
     
     
       18. The method of  claim 12 , wherein determining that one or more solar cells of the one or more solar panels failed comprises:
 determining, based on a thermal image, that thermal energy of a solar cell of the solar panel exceeds thermal energies of one or more other solar cells of the solar panel by at least a threshold difference amount; and 
 in response, determining that at the solar cell of the solar panel failed. 
 
     
     
       19. The method of  claim 12 , wherein determining that one or more solar cells of the one or more solar panels failed comprises:
 determining, based on a thermal image, that a string of solar cells of the solar panel are overheating; and 
 in response, determining that the string of solar cells failed. 
 
     
     
       20. An apparatus comprising:
 one or more computer-readable media; and 
 program instructions stored on the one or more computer-readable storage media that, when executed by one or more processors onboard an aerial vehicle, direct the one or more processors to at least: 
 determine a flight path for aerial vehicle for inspection of one or more solar panels; 
 navigate the aerial vehicle according to the flight path; 
 obtain, at multiple geo-spatial locations, respective thermal images of the one or more solar panels; 
 determine, based on the obtained thermal images, that one or more solar cells of the one or more solar panels failed; and 
 generate a report indicating the failure.